16405002181 has 2 divisors, whose sum is σ = 16405002182. Its totient is φ = 16405002180.

The previous prime is 16405002143. The next prime is 16405002233. The reversal of 16405002181 is 18120050461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14915736900 + 1489265281 = 122130^2 + 38591^2 .

It is a cyclic number.

It is not a de Polignac number, because 16405002181 - 2²³ = 16396613573 is a prime.

It is a super-2 number, since 2×16405002181² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16405000181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8202501090 + 8202501091.

It is an arithmetic number, because the mean of its divisors is an integer number (8202501091).

Almost surely, 2^16405002181 is an apocalyptic number.

It is an amenable number.

16405002181 is a deficient number, since it is larger than the sum of its proper divisors (1).

16405002181 is an equidigital number, since it uses as much as digits as its factorization.

16405002181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 28.

The spelling of 16405002181 in words is "sixteen billion, four hundred five million, two thousand, one hundred eighty-one".